There are some of the best optical illusios I've ever seen. They will totally mess with your perception. The best thing is that they are all in real places, not just pictures on a computer.
Tokyoflash Treasure Hunt - Win a Tokyoflash Watch of Your Choice!
Going on right now: Tokyoflash Treasure Hunt #26. Win a Tokyoflash watch and neat stuff from the NeatoShop. It's fun and easy to play: Link